A variable air volume box controls the air flow to a given space. When the space is unoccupied, the box closes off the heat and cooling to a minimum flow or turns it off when a building is not being used. When the airflow is reduced, the fan that supplies the air slows down, reducing the horsepower applied to the fan and the amount of electricity consumed. A signal is then sent to the cooling and heating pumps to slow down and reduce consumption. This matches supply with demand because if a building is empty it does not need to be heated or cooled at the same level as an occupied building.